not sure about TM800 version but the TM600 URSR image has all the services removed ftp/telnet/webui etc, and can only be put back to "UR" with null modem.
No Telnet and no FTP, totally locked down - probably to stop you from getting the IP address of the free server - which is silly as the images come with CCcam PPanel pre-installed.
BTW, I can't see any difference between the new one and the old one, maybe some tweaks done under the hood.